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| Titel |
Taxon-specific responses of Southern Ocean diatoms to Fe enrichment revealed by synchrotron radiation FTIR microspectroscopy |
| VerfasserIn |
O. Sackett, L. Armand, J. Beardall, R. Hill, M. Doblin, C. Connelly, J. Howes, B. Stuart, P. Ralph, P. Heraud |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 20 ; Nr. 11, no. 20 (2014-10-20), S.5795-5808 |
| Datensatznummer |
250117649
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| Publikation (Nr.) |
 copernicus.org/bg-11-5795-2014.pdf |
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| Zusammenfassung |
| Photosynthesis by marine diatoms contributes substantially to global
biogeochemical cycling and ecosystem productivity. It is widely accepted that
diatoms are extremely sensitive to changes in Fe availability, with numerous
in situ experiments demonstrating rapid growth and increased export of
elements (e.g. C, Si and Fe) from surface waters as a result of Fe addition.
Less is known about the effects of Fe enrichment on the phenotypes of
diatoms, such as associated changes in nutritional value – furthermore, data on
taxon-specific responses are almost non-existent. Enhanced supply of
nutrient-rich waters along the coast of the subantarctic Kerguelen Island
provide a valuable opportunity to examine the responses of phytoplankton to
natural Fe enrichment. Here we demonstrate the use of synchrotron radiation
Fourier Transform Infrared (SR-FTIR) microspectroscopy to analyse changes in
the macromolecular composition of diatoms collected along the coast and
plateau of Kerguelen Island, Southern Ocean. SR-FTIR microspectroscopy
enabled the analysis of individual diatom cells from mixed communities of
field-collected samples, thereby providing insight into in situ
taxon-specific responses in relation to changes in Fe availability.
Phenotypic responses were taxon-specific in terms of intraspecific
variability and changes in proteins, amino acids, phosphorylated molecules,
silicate/silicic acid and carbohydrates. In contrast to some previous
studies, silicate/silicic acid levels increased under Fe enrichment, in
conjunction with increases in carbohydrate stores. The highly abundant taxon
Fragilariopsis kerguelensis displayed a higher level of phenotypic
plasticity than Pseudo-nitzschia spp., while analysis of the data
pooled across all measured taxa showed different patterns in macromolecular
composition compared to those for individual taxon. This study demonstrates
that taxon-specific responses to Fe enrichment may not always be accurately
reflected by bulk community measurements, highlighting the need for further
research into taxon-specific phenotypic responses of phytoplankton to
environmental change. |
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